An ex vivo zebrafish heart model for oxidative stress studies

Oxidative stress is a key driver of heart disease, but existing single-cell models lack the complexity of cardiac tissue. Developing advanced in vitro systems is therefore critical. This study aimed to develop a zebrafish heart oxidative stress model that can more closely mimic the in vivo effects and exploring its potential applications in in vitro research. Zebrafish hearts were isolated and cultured in optimized L15 medium. Oxidative stress was induced using hydrogen peroxide (H₂O₂), with reactive oxygen species (ROS) production monitored via 2',7'-Dichlorodihydrofluorescein diacetate (DCFH) staining. Apoptosis was assessed by TUNEL assay, and sarcomere integrity was evaluated using F-actin staining. The protective effects of vitamin C were also examined. The optimized culture medium maintained heart viability and structural integrity. H₂O₂ treatment induced dose- and time-dependent increases in ROS levels, apoptosis, and sarcomere disorganization, closely resembling in vivo oxidative injury. Notably, vitamin C significantly mitigated these effects, demonstrating the model's utility for drug screening. This study has for the first time established an oxidative stress model using ex vivo zebrafish hearts, offering a new research platform to understand in vivo oxidative stress mechanisms and develop relevant therapies.